


raison d'être

by necroeffect



Category: Undertale (Video Game)
Genre: Alternate Universe - Fellswap Gold, Alternate Universe - Soulmates, Angst, Both of them, Eventual Romance, I Don't Even Know, M/M, Other Additional Tags to Be Added, Papyrus (Undertale) Knows More Than He Lets On, References to Depression, Sans (Undertale) Remembers Resets, Sanscest - Freeform, Soulmates, no beta we die like men, reposted
Language: English
Status: In-Progress
Published: 2019-01-06
Updated: 2019-01-06
Packaged: 2019-10-05 11:04:29
Rating: Not Rated
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,894
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17323832
Author URL: https://archiveofourown.org/users/necroeffect/pseuds/necroeffect
Summary: The fabric was smooth against his own fingertips, almost impossible not to touch when seeking his brother's hands that were buried in the material. The sensation of a magical imprint ofstability/control/safety/affectionbrushed across his senses in steady, soothing waves."Where did you even get this from, brother?"





	raison d'être

**Author's Note:**

> i initially took this down because i was sort of worried about jot not really liking the liberties i was going to take with swapfell gold. but i got asked to put this back up, and i don't, hate this. on the contrary. 
> 
> so yolo and shit yeah. i hope this acceptable, and bear in mind most of the information i retrieved about this AU was roughly translated from other languages so i apologize for any discrepancies in the future.

When Papyrus had seen Sans slowly clamber downstairs,  _terribly_  and nearly  _inexcusably_ late for his breakfast spaghetti, without the presence of his beloved blue parka was when Papyrus should have known something was  _very_ wrong. His brother  _never_  was without the thing, and seemed to be more associative of Sans than the skeleton himself at times. Papyrus for the life of him could not recall the last time he had seen his brother without it. Certainly it must have been at least  _years_.

Which definitely wasn't healthy, now that Papyrus was really thinking about it.

However, Papyrus couldn't necessarily judge him. Sans' gift to him from when he was but a baby bones rarely left him the very same. The lanky skeleton absentmindedly fingered the scarf that hung loosely around his cervical spine, the frayed and worn edges a comforting sensation. It was a comforting weight, and the idea of being without it left him uncomfortable.

Regardless, the sight had been as jarring as it was indicative that something was amiss with his brother. The suspicion was only supplemented by how dazed and disoriented Sans seemed to be. He was drinking in his surroundings like a man dying of thirst, as well as spontaneously hugging him like he hadn't seen him for  _months._  Not that Papyrus didn't appreciate his brother's affection, but the way he had done so had seemed almost...  _desperate_. Like he was afraid Papyrus would vanish if he let go.

How he deflected his questions, and acted as though nothing was wrong did not help matters. He insisted nothing was out of the ordinary. That he had opted for a change of pace. Turning over a new leaf, of sorts.

Papyrus couldn't find it in himself to press on, and conceded to allow his brother to tell him in his own time what had happened. His behavior was disconcerting, but really there was nothing  _concrete_  for Papyrus to latch onto to force Sans' hands and admit what was plaguing him aside from his change in attire.

That had been his first mistake.

Papyrus had known his brother had been hiding something, knew that Sans was the last person to spontaneously turn over a new leaf. He would let the leaf turn him over first, if anything. The loss of the blue garment had been a harbinger for the deterioration of Sans' behavior and lively hood.

There was no excuse for his following blunders, that lead to his current predicament. How Papyrus had taken mercy on his brother as he refused to confide in him, seeming so  _tormented_ when he asked that Papyrus had felt like it was cruel to continue to press. How he had allowed Sans to sleep for much longer than was healthy, and allowed him to skip meals frequently. And even with all the sleep he seemed so tired. So listless and lethargic.

He had been too easy on him. Papyrus should have asked, should have made his brother tell him what was wrong. The signs had been there, so glaringly obvious.

When Sans still refused to awaken for over a day - to wake up at all - was when Papyrus felt the suffocating guilt of what he had done. He was a failure as a brother.

Sans had taken care of him for so long, had done so much for him. And yet he let this happen.

The knowledge of monsters falling down to a lack of HOPE wasn't quite public knowledge, but Papyrus knew many things that most weren't privy to. That was merely a fact. He was The Great Papyrus, after all.

With Alphys' confirmation he was devasted, beret with regret and remorse. Terrified and guilty all at once. Sans had staved off Falling Down for so long, despite his chronic depression.

His brother had always seemed so invincible. Sans had always hung on, despite everything.

Sans promised him he would try his best. That he would always be there for him, no matter what.

He had never broken a promise before. He took great lengths to avoid making them, after all, because of how seriously he took them.

_"I'm sorry Paps," Sans rasped. His voice deep, almost hoarse from slumber._

_"What are you apologizing now for, brother? Honestly..." He shook his head, mirthful and affectionately patting his brother. "Whatever it is, it's fine, Sans."_

_Sans didn't reply, and only then did Papyrus really see how exhausted his brother looked. The soft note of sadness that permitted his ever-grinning expression. He parroted the phrase, mumbling it softly before falling back asleep._

That was his last mistake.

"I'm s-sorry, Papyrus... There's l-little we can do until the more extensive SOUL tests come back. A-and even... even then..." Alphys' voice quivered, pulling him out of his thoughts. He nodded in acceptance, a gratitude ringing loudly against what had become a makeshift med bay.

The lizard monster seemed to jump at his volume, before speaking. "I-I'll leave you two alone then." He shot her a grateful look as she scurried out the door, her own sorrow at the situation palpable.

He hadn't even known Alphys  _knew_  Sans that well, but he shouldn't be surprised. His brother was incredibly popular and well-liked. Papyrus' nature and charisma must have rubbed off on him.

Or it was simply another thing he didn't know about his brother.

"What happened, Sans?" He asked the other skeleton, the words feeling rough as they left his maw. His phalanges rubbed small circles against his brother's capitate and hamate bones, unable to reach his fingers that were twisted in vivid red spider silk. The smaller skeleton's determination to not be separated from the fabric - even in his current state - was something baffling.

Sans had been in possession of the material since Papyrus had found him in his current condition. When they had finally bothered to peel him out of his clothes and get better access to his SOUL to get a read on his STATS or possible vitals, he had clung onto the fabric for dear life. They had almost thought he had been coming to when he brought the spider silk closer.

It wasn't an unheard of reaction from those who had recently fallen down to  _react_  to something that bothered them, until their condition really settled. However, the intensity of the reaction left them baffled. Papyrus still recalled Undyne's accusation that his brother was  _faking it_ , and Alphys bewilderment.

Nonetheless, his vitals and flavor text were still indicative of a SOUL that was barely hanging on as is. That was deprived of one of it's core materials. Love,  _hope_ and compassion were what monster's SOULs were said to be made of, after all.

He absentmindedly studied the cloth, what appeared to be a decorative scarf with pointed edges flowing from his hands. The quality of the silk was incredibly fine and of expensive quality, according to the spiders he had inquired about it. It had been Undyne's idea to ask about it, given Sans'...  _reaction_ to the offending object and Papyrus' lack of knowledge of it. He had never seen it before.

The spiders had no affiliation with garment either, if they were to be believed. The attempt to gain information only left them with even more questions. Where in the underground did you get  _spider silk_ not made by  _the spiders?_

 _Why do you keep things like this from me, Sans?_  The thought made frustration and helplessness mount.

"All of this knowledge does me nothing when you don't tell me things, Sans." The words slipped out before Papyrus realized he hadn't even meant to speak them aloud. "How am I supposed to help you if you won't tell me anything, brother?" His eye sockets burned.

Papyrus told him. He was aware of the nature of their world, the coding, as much as Sans was, after all. But his brother was still secretive, still tried to protect him and held things from him. "Why won't you tell me...?"

The vividly red scarf seemed to mock him. The fabric was smooth against his own fingertips, almost impossible not to touch when seeking his brother's hands that were buried in the material. The sensation of a magical imprint of  _stability/control/safety/affection_  brushed across his senses in steady, soothing waves.

"Where did you even get this from, brother?"

 

* * *

 

_"You're so sweet! The best Soulmate ever!"_

Sans smiled lightly at the pair of monsters leaving his stand, and sighed as he got ready to close down his  _"sentry station_ ," for the day. The pair of monsters, a Vulkin and a Tsunderplane, had been a very affectionate couple. Sans thought it was adorable, personally.

He was happy for them. It wasn't hard to find your Soulmate in the Underground, given the low population and tight knit community, but it was still something to be celebrated.

Something in him ached at the direction of his thoughts, the thought of Soulmates bringing a bitter taste to his mouth. He tried not to think about it, but the Vulkin's words still persisted in his mind, echoing loudly in his skull.

 _"The best Soulmate ever!_ "

The concept was cliche and sappy, but a part of him longed for it. The idea that someone was out there, that was made for you and  _only you_. That sort of relationship - a part of him ached for it. For the comfort someone like that would provide.

strikeHe was so tired./strike

But he had searched and searched and  _searched_. He had combed through the Underground tirelessly, timeline after timeline. He had met every monster in the underground, he had checked  _every one of them_ , only to come out empty handed. His best efforts had been disregarded.

He was alone.

The homicidal flower had seen his endeavors and had mocked him tirelessly for it. The multitude of deaths Sans had suffered after he had tore the flower to shreds in retribution had been entirely worth it. (Though his thoughts on the matter at the time, when he was being torn apart bone by bone, may have been slightly different.) The taste of revenge still made Sans' new discovery almost easier to bear.

Almost.

A part of him still believed firmly that the fact he didn't have a Soulmate was a side effect of the accident. The way the CORE's magic had dripped into his SOUL had ended up changing the properties of it. The very essence of his being had been altered in that catastrophic event. It would be entirely plausible that his compatibility with his assigned Soulmate had been broken.

It would just be one more thing the accident at the core had cost him.

There was also still the low, marginal chance they hadn't been born yet. Or possibly even that they were out there somewhere, Aboveground. But both were so unlikely, especially given his rising age, that he had simply... given up.

It was futile, really.

In hindsight, Sans wished he simply had left well enough alone and followed tradition, waiting to meet his  _fated one_. He should have listened, and not gotten too overzealous. Not gotten too desperate. But he hadn't considered the possibility of coming out empty handed at the time. To Sans, it hadn't been a possibility. He had been so sure they were out there. So very certain there was someone waiting for him.

(That feeling still remained. But it couldn't be.  _Couldn't be._ )

Sans had been mistaken, and it cost him. He sunk deeper into depression than he had been before, even when he had to move to Snowdin and take care of Papyrus on his own. The knowledge that he was  _broken_  and sentenced to be alone, coupled with being pulled through time and space so much that his actions were  _meaningless_  had been - too much at the time. Even now, the burden of that knowledge hurt him.

strike He had just wanted  _something_  to make it easier to bare.  _Anything._ /strike

He should just be grateful to have his wonderful brother, Sans told himself viciously. To want anything more was selfish of him.  _Be happy with what you have, Sans._

But despite himself, a part of him still ached. A part of him still grieved for what he missed.

Nevertheless, the mention of the subject had brought up long buried emotions. Grief and longing seized him and clung to his mind like a shadow. He didn't want to admit that he was unsettled, or remotely upset but it was undeniable.

He  _knew_ better than to make a shortcut under such conditions. Traveling through time and space necessitated precision and high magic control from Sans. He had learned the hard way when he had been initially learning how to manipulate his newly changed magic. It was incredible volatile and functioned on intent with a higher sensitivity than previously. Trial and error had taught him that.

Not to mention the one time he intended to shortcut home and had somehow ended up in Undyne's home. When she had been inside. That had been an incredibly nightmarish experience that required a  _lot_  of bullshitting to get out of.

Needless to say, he definitely knew better.

Nevertheless, he knew almost immediately that the shortcut had been botched by the sheer  _pull_  on his SOUL's magic. It required magic but certainly not  _that_  much, and it simply kept pulling. Sans' SOUL lingered in the void as the magic failed to complete, the creeping sensation of static beginning to brush against his bones and the gaping darkness seeming to scream.

He wasn't supposed to linger here for this long,Sans realized with a building sense of foreboding. Had he done something wrong? He was just 'porting home, nothing special. What was happening?

By the time he considered breaking off the magic and trying to rip back through time and space in a different way, the exhaustion of mana depletion swarm his senses. His intent almost faltered at the sensation, his determination a step away from buckling under the slow panic that was descending across his mind. It just kept  _taking_ and  _taking._

_Why wasn't he going-_

And then reality bled back around him, the brightness of  _snow_  and  _light_  nearly blinding in comparison to the all consuming darkness of the void. The sensation of frigid air brushing across his bones was a welcome, sweet relief.

It took a moment for Sans' eye lights, nearly unlit from the lack of mana in his system, to truly see and recognize his surroundings. He knew he was in Snowdin by the sheer temperature, but the blurred red buildings around him offered nothing familiar. He attempted to move, search for something close to  _home_  but his body gave out on him at the first modicum of effort. After that, it was as though his body's ability to perceive  _feeling_ finally registered as his SOUL panged with mana depletion to a painful degree. His legs buckled beneath him, the frigid snow -  _definitely Snowdin -_ beneath his uncovered femurs almost soothing as his bones ached hotly.

Everything went dark.

 

* * *

 

 

Consciousness returned to Sans slowly, and waking up was nothing short of a painful process. His SOUL  _ached_  in way he hadn't experienced for a long time, and his magic felt stretched terribly thin. Agony was Sans' steady companion until he tried to gather his bearings, or at the very least until he attempted to move.

Sans was met with immediate resistance. His magic struggled to move his limbs, and even then he was met with the sensation of metal cuffs heavily restricting his movement. The grogginess of his exhausted state fled him as panic gripped him. He attempted to summon his eye lights, despite the risks of doing so in such a magic depleted state. Sans was met the sensation of something  _coldcoldcold_ stilling his magic before it could form, preventing his sight.

His form pulsed with pain after the attempt, and his breathing becoming shallow and rapid in the panic that bubbled forth. He was so weak he could barely hold himself together, and he was being held  _captive_. He didn't know where he was, he couldn't  _see_. Sans was vulnerable and at another's MERCY.

Angel, he must have gone missing.  _Papyrus was probably-_

Sans found himself stilling sharply at the sound of voices and muted footsteps, somewhere vaguely to his right. The sounded muffled and distant, but definitely nearby. Perhaps in an adjacent room? The discussion sounded agitated, and sharp from what he could hear. Any other thought was relinquished as the voices got louder, closer to him. He could tell it was only two voices, though there could be more among them.

The heated discussion fell silent right before they were close enough for Sans' to discern what was being said. The sound of footsteps continued steadily despite the sudden silence, until it stilled abruptly nearby.

Sans clenched his jaw tightly in anxiety, but attempted to settle his ruffled mindset. Being upset would gain him no leverage here.

It never did, honestly.

However, was the distant sound of movement.

If Sans could tense further, he would have at the distinct sound of a door being opened close by. The low clicking of shoes -  _heels?_  - against a smooth flooring was booming against the thick silence that had permeated the room prior.

_cl-ick. cl-ick. cl-_

The sound stopped. The monster before him was close.

"I know you're awake."

 


End file.
